1. Technical Field
The present disclosure relates to amplifier circuits, and particularly to an amplifier circuit capable of rejecting image signals.
2. Description of Related Art
In wireless communication, when wireless signals are received by communication terminals, the communication terminals often need to convert frequencies of the received signals into working signals capable of being transmitted and processed in the communication terminals. However, the frequency conversion operations may generate image signals interfering with wireless communication. Thus, the communication terminals generally require filters used therein for filtering the image signals.
After the frequency conversion operations, the working signals are generally inputted into amplifier circuits to be amplified, and then are transmitted to other functional modules (e.g., decoders or speakers) of the communication terminals to be further processed. Thus, in most communication terminals, the filters for filtering image signals are integrated with the amplifier circuits, such that the image signals are filtered before the working signals are further processed. For example, surface acoustic wave (SAW) filters are often integrated with amplifier circuits of wireless communication terminals to filter image signals. However, conventional filters integrated with the amplifier circuits, such as the SAW filters, are usually expensive, which increases cost of the communication terminals.
Therefore, there is room for improvement within the art.